Report wording need help

It's been a week since my diagnostic mammogram and u/s and I finally got the results in my MyChart account. The radiologist said that it seemed to be on the benign side but I needed a biopsy to make 100% sure. I was hoping that my report would clarify whether I was considered 4a, b, or c but it only says 4.

Anyway thoughts on the words, what I may have, and what they may find during the biopsy tomorrow will be appreciated. I know nothing expect the biopsy is 100% but I would like to have some idea before my results appointment next Tuesday.

Wording from mammogram and u/s

IMPRESSION: Solid mass left upper outer quadrant, possibly a fibroadenoma but not entirely typical

FINDINGS: The breast tissue is heterogeneously dense, which may obscure small masses. There is mass in the upper outer quadrant, mid depth, equal density, mildly lobulated.

Ultrasound demonstrates a solid mass, upper outer quadrant, 8 cm from the nipple, 17.6 x 6.5 x 11.5 mm. It is hypoechoic, with parallel orientation. Margins may be slightly irregular.

Axilla: No abnormal lymph nodes.